.TH std::map::value_compare 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::map::value_compare \- std::map::value_compare

.SH Synopsis
   class value_compare;

   std::map::value_compare is a function object that compares objects of type
   std::map::value_type (key-value pairs) by comparing of the first components of the
   pairs.

.SH Member types

   Type                                                         Definition
   result_type (deprecated in C++17)(removed in C++20)          bool
   first_argument_type (deprecated in C++17)(removed in C++20)  value_type
   second_argument_type (deprecated in C++17)(removed in C++20) value_type

   These member types are obtained via publicly inheriting                \fI(until C++11)\fP
   std::binary_function<value_type, value_type, bool>.

.SH Protected member objects

   Compare comp the stored comparator
                \fI(protected member object)\fP

.SH Member functions

   constructor   constructs a new value_compare object
                 \fI(protected member function)\fP
   operator()    compares two values of type value_type
                 \fI(public member function)\fP

std::map<Key,T,Compare,Alloc>::value_compare::value_compare

   protected:
   value_compare( Compare c );

   Initializes the internal instance of the comparator to c.

.SH Parameters

   c - comparator to assign

std::map<Key,T,Compare,Alloc>::value_compare::operator()

   bool operator()( const value_type& lhs, const value_type& rhs ) const;

   Compares lhs.first and rhs.first by calling the stored comparator.

.SH Parameters

   lhs, rhs - values to compare

.SH Return value

   comp(lhs.first, rhs.first)

.SH Exceptions

   May throw implementation-defined exceptions.
